Th present invention relates generally to the field of aircraft weapon control radar systems and more particularly to such a system which provides target tracking capability for a full 360.degree. in azimuth and elevation.
Pilots of U.S. military aircraft carrying semi-active missiles are experiencing difficulty in launching the missiles against enemy fighters in an air combat maneuvering (ACM) environment. The semi-acitive missile weapon systems currently employed were designed to intercept enemy bombers attempting to destroy or otherwise threaten the U.S. fleet and/or continental defenses. In the mechanization of these systems, the look angle of the search and track fire control radar was established to cover the forward sector of the launching aircraft. In most cases this sector consisted of a cone of microwave illumination .+-.60.degree. around the aircraft datum line. Missiles can be launched against the airborne target whenever the system indicates to the pilot that the target is in range and that the aircraft is headed in the proper lead pursuit course. These launches were made against non-maneuvering targets at ranges of 3 to 15 miles. As the systems were designed to combat non-maneuvering targets, they performed adequately.
Many of these aircraft are now being used in an ACM environment. They are operating in air space which is occupied by commercial and friendly military aircraft as well as enemy aircraft. Because of the necessity of positive identification all targets must be visually identified prior to launching a missile. This requirement changes the scenario from a nonmaneuvering airborne intercept (AI) environment to an ACM environment. The usual ACM situation develops when the interceptor is tracking the enemy target at long range up to the point of visual identification at which time or shortly thereafter the target passes to the rear of the interceptor exceeding the gimbal limits of the radar. Immediately, the target turns back 180.degree. toward the interceptor as the interceptor continues on its course. After flying the course for a calculated distance, the interceptor turns back toward the target endeavoring to get into a missile firing position. Often, the length of time required for the radar system to re-acquire the target, which can only be accomplished when the target has reached a position in space that falls within the gimbal limits of the interceptor radar, precludes a successful missile launch from being executed. As the target and interceptor turn to get into firing position, the interceptor pilot must wait until the target is within the radar gimbal limits. Then the radar must re-acquire the target, settle down to track the target, generate signals relative to closing rates and compute the proper launch point in angle and range. In the classic case there is not enough time as the aircraft approach each other to execute a successful launch of the missile.